The present invention relates to a gas insulation switch suitable for earth anti-warming measures. For example, as described in Engineering Report of Japanese Electrotechnical Committee, No. 552, xe2x80x9cApplication Guide of Gas Insulation Switch (GIS)xe2x80x9d (issued on July 1995), the gas insulation switch (hereinafter called GIS) comprises a single or a plurality of gas insulated units and is installed in a switching station or substation. Each gas insulated unit comprises a grounding steel tank containing high voltage units such as a conductor unit, conductor connection unit, and switching unit and insulating spacers arranged so as to reserve an insulation distance between the high voltage units and the grounding tank, or so as to support the high voltage units, or so as to divide the grounding tank for each gas. As insulating gas, sulphur gas hexafluoride (hereinafter called SF6 gas) having superior insulation performance and arc extinguishing performance has been used since 1970.
The GIS containing all charged units in the grounding steel tank is hardly affected by weather conditions, superior in environment resistance, and advantageous in reduction of the site of a switching station or substation, so that it has made rapid progress. Recently, however, SF6 gas used for insulation of the GIS has an earth warming coefficient of about 24000 times of that of carbon dioxide (CO2) and it is indispensable to reduce the amount used in the future from a viewpoint of anti-warming measures. As one of the SF6 gas use amount reduction methods, application of mixed gas may be considered. However, when the gas is used for all the units constituting the GIS, the processing method in the case of an emergency such as gas separation is complicated. Therefore, it cannot be always said that it is a valid method.
The present invention is realized in consideration of the aforementioned conditions and provides a gas insulation switch for reducing the SF6 gas use amount. The present invention also provides a gas insulation switch for reducing the SF6 gas use amount without damaging the insulation performance and arc extinguishing performance. The present invention also provides a gas insulation switch for simply processing insulating gas and reducing the SF6 gas use amount.
The first invention is a gas insulation switch comprising a container charged with insulating gas which contains an electric conductor and at least a pair of contractors which can be connected or disconnected and which is divided into a plurality of gas sections, sealed with insulating material, and wherein as the insulating gas of a gas section containing no separable contactors among the plurality of gas sections, insulating gas having a smaller earth warming coefficient than that of SF6 gas is used.
The second invention is a gas insulation switch for at least a pair of separable contactors comprising a unit housing a breaker in a first grounding tank and a unit housing an electric conductor supported by an insulating support member in a second grounding tank, wherein the first grounding tank is charged with SF6 gas and the second grounding tank is charged with insulating gas having a smaller earth warming coefficient than that of the aforementioned SF6 gas.
The third invention is a gas insulation switch comprising a unit housing a breaker in a first grounding tank, a unit housing a conductor supported by an insulating support member in a second grounding tank, and a unit containing a gas insulating switch and a grounding switch in a third grounding tank, wherein the first grounding tank is charged with SF6 gas and the second and third grounding tanks are charged with gas having a smaller earth warming coefficient than that of SF6 gas.
The gas insulation switches of the first to third inventions mentioned above use one of nitrogen gas, and air, as insulating gas having a smaller earth warming coefficient than that of SF6 gas. In the gas insulation switch of the third invention, the second grounding tank is charged with nitrogen gas or air and the third grounding tank is charged with mixed gas.
In the gas insulation switch of the second or third invention mentioned above, the pressure in the grounding tank charged with insulating gas having a smaller earth warming coefficient than that of SF6 gas is set higher than the pressure in the grounding tank charged with SF6 gas. The grounding tanks are mechanically connected via insulating spacers having conical convexes and arranged so that the convexes are located on the side of the grounding tanks charged with insulating gas having a smaller earth warming coefficient than that of SF6 gas. The grounding tanks charged with insulating gas having a smaller earth warming coefficient than that of SF6 gas are used as SF6 gas collector containers.
The fourth invention is a gas insulation switch comprising a first unit housing a breaker in a grounding tank and a second unit housing an electric conductor supported by an insulating support member in a grounding tank, wherein the grounding tank of the first unit is charged with SF6 (sulphur hexafluoride) gas, and the grounding tank of the second unit is charged with insulating gas having a smaller dielectric strength than that of the aforementioned SF6 (sulphur hexafluoride) gas at the same pressure, and furthermore the insulation size of the second unit is made larger than the insulation size of the first unit in correspondence with the smaller dielectric strength.
The fifth invention is a gas insulation switch comprising a first unit housing a breaker in a grounding tank and a second unit housing an electric conductor supported by an insulating support member in a grounding tank, wherein the grounding tank of the first unit is charged with SF6 (sulphur hexafluoride) gas, and the grounding tank of the second unit is charged with insulating gas having a smaller dielectric strength than that of the aforementioned SF6 (sulphur hexafluoride) gas at the same pressure, and furthermore the pressure in the grounding tank of the second unit is made higher than the pressure in the grounding tank of the first unit in correspondence with the smaller dielectric strength, and the thickness of the grounding tank of the second unit is made wider in correspondence with the higher pressure in the grounding tank.
The gas insulation switch of the fourth or fifth invention mentioned above uses gas having a smaller earth warming coefficient than that of SF6 (sulphur hexafluoride) gas as insulating gas having a smaller dielectric strength than that of SF6 (sulphur hexafluoride) gas at the same pressure and the gas having a smaller earth warming coefficient is nitrogen gas, or air.